Patent GB-417264-A (GB)
Title: Improved apparatus for controlling traffic more particularly on single line railways
IPC: B61L23/24
Filed: 1933-03-29
Abstract: 417,264. Token systems for controlling railway traffic. COUPER, J. D. C., 4, Dean's Yard, Westminster. March 29, 1933, Nos. 9461 and 14997. [Class 105.] Token apparatus for controlling railway traffic is adapted for unattended working by arranging that in the initial or normal state of the apparatus the source of E.M.F. is either directly connected to the line or is applied to the line through the intermediary of a relay operated by current from the station at which a token is sought to be obtained. In the form shown in Fig. 1, the two instruments are connected by two line wires 1, 2 and an earth return. To obtain a token at station X the push 6 is depressed, so connecting in the polarized relay 4 to the line wire 1 which at station Y is connected over the sections 9, 7 of the reversing switch and undepressed push 6 to the negative side of battery 3 at this distan station Y ; thus the polarized relay 4 at station X is correctly energized to release the lock on the token apparatus. Unattended working is possible as it will be seen that an attendant is not required at the far end Y. When a token is removed, the reversing switch is operated so that line 1 is now connected with the negative sides of the batteries 3 at stations X and Y which thus act in opposition, and moreover line 2 would, on depression of push 6 at station X, be connected merely with the polarized relays 4 at stations X and Y. The relays cannot therefore now be energized by the depression of a push 6 and even if a cross connection arose between the lines 1 and 2 the polarized relays would be energized in the wrong direction and would not release the lock. When the token is inserted in either instrument the reversing switch of that instrument is changed over and sets the connections once again to an effective state. Fig. 5 shows an arrangement in which the lock relay 4 is a neutral relay energized from the local battery under the control of a polarized relay 13 having associated therewith a push 12 and indicator 11. To obtain a token, the push 12 is closed and if no tokens are out the indicator shows " token free and the polarized relay 13 is correctly energized to effect the local energization of a relay 10 which removes a lock on the push 6 so that this push 6 can be depressed to energize the lock relay 4 ; the push 6 maintains the push 12 depressed. A drum switch may be substituted for the reversing switch sections and the push 6. A single line wire and an earth return only are used with the arrangement shown in Fig. 7 which comprises a drum commutator, a drum switch device 20, and pick up and stick relays 26-28 for the control of the polarized relay 13 and lock relay 4. To obtain a token at station X the drum switch 20 is moved from the a to the b position so applying battery positive to the line wire 1 with the result that at station Y, where the commutator is at the 180‹ position, the pick-up relay 26 is energized and this in turn energizes relay 28 and the stick winding 27 at Y by the batteries 3 at stations X and Y being in series for this particular circuit. On moving the drum switch 20 at X to position c, the polarized relay 13 at X is energized, but in the wrong direction since it is energized by battery 3 at X; only when the drum switch 20 has moved to position d is the polarized relay 13 at X correctly energized since at this position it is energized by the battery 3 at the distant station Y ; this distant battery applies its negative pole to the line wire 1, whereas the local battery 3 when in circuit applied its positive pole to the line wire 1. The lock relay 4 is now locally energized to free the commutator which is turned 180‹ by the withdrawal of a token. Fig. 15 shows apparatus which can be changed over for attended or unattended working and also using only a single line wire 1. The apparatus is similar to that shown in Fig. 7 and additionally includes bell signals, three-position indicators, and resistances paralleling the polarized relays to prevent the stick relays dropping during the reversal of current which might otherwise be slowed up by the inductive effect. Bell signals are exchanged by pushes 33 which on depression briefly close a spring contact, whereby battery is applied to the line and operating the polarized relay 13 either way at the distant station rings a bell 34. To obtain a token at station X, bell signals are exchanged and at station Y a second push 35 is then depressed so that when the signalman at station X moves his drum switch 20 to position b, the battery positive is applied to the line 1 and correctly energizes polarized relay 13 at station Y. This relay then locally energizes the pick-up relay 26 so that the stick relays 27, 28 are then energized by the batteries 3 acting in series, the circuit including the depressed push 35 at station Y. The resistance 31 at station X is inserted between the line 1 and earth. On moving the drum switch to position c the battery 3 at station Y, having its negative pole applied to the line 1, correctly energizes the polarized relay 13 at station X, the resistance 31 allowing the suddenly reversed current to flow immediately since it offers no inductive retardation and thus there is no possibility of the stick relays dropping. A token can now be withdrawn incidentally reversing the commutor and breaking the stick circuit of the relays 27, 28. The lock relay 4 and a " train leaving " indicator winding 36 are locally energized over a contact of the polarized relay 13 at an intermediate stage of the movement. The drum switch is then allowed to return and at position b the battery 3 at station X applies negative to the line 1 thus energizing the polarized relay 13 at station Y in the wrong direction but causing a " train coming " indicator winding 37 to be - energized and the bell to ring so notifying the signalman that he may release his push 35. Mechanical interlocking requires the drum switch to be at position c for the commutator to be released. To insert a taken the drum switch is moved to position c, the token is inserted, and the switch is allowed to return ; at position b the battery 3 at station X applies its positive pole to the line 1 (the commutator having been restored to its first position by inserting the token) and so correctly energizes relay 13 to operate the pick-up relay 26 and the indicator release winding 38 at station Y. The indicator at station X was released by the return movement of the commutator. For unattended working the pushes 35 are locked in the depressed position, this locking requiring the signals and points to be correctly set and locked.